Apparatus for the construction of vertical tubular concrete structures



May 5, 1970 R. D. FISHER APPARATUS FOR THE CONSTRUCTION OF VERTICAL TUBULAR CONCRETE STRUCTURES Filed Feb. 13, 1967 FIG. I

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RICHARD D. FISHER United States Patent 3,509,606 APPARATUS FOR THE CONSTRUCTION OF VERTICAL TUBULAR CONCRETE STRUCTURES Richard D. Fisher, Milton-Freewater, Oreg., assignor to De Muth Steel Products Company, Schiller Park, Ill., a corporation of Illinois Filed Feb. 13, 1967, Ser. No. 615,770 Int. Cl. E03b 11/00 US. Cl. 25-124 7 Claims ABSTRACT OF THE DISCLOSURE Method and apparatus for-constructing vertical, tubular concrete structures, such as silos and the like, wherein the concrete is poured on a continuous or intermittent basis comprising a vertically extending form structure having spaced inside and outside form walls. A horizontal Work platform is mounted inside the form structure and is connected around its periphery to the inside form wall to support the structure. An independent, surface supported, vertical scaffold structure is constructed inside the form structure for supporting the platform, and includes a plurality of vertical posts. The scaffold structure includes a plurality of sections adapted to be stacked vertically upon one another to support the platform as it is elevated. Lifting means interconnected between the work platform and the posts of the scaffold sections for elevating the platform and form structure as pouring of the concrete proceeds at ever increasing elevations until the silo is completed.

The present invention relates to a new and improved apparatus for constructing vertical, tubular concrete structures, such as silos, storage 'bins, and the like, wherein the concrete is poured on a continuous basis and the forms are elevated until the poured structure reaches the desired height.

In constructing concrete silos, storage bins, and the like, it is highly desirable that the construction process proceed as rapidly as possible. In prior arrangements, using slip forms, the forms are usually supported on the reinforcing rods in the poured silo walls. This arrangement usually requires a substantial number of hydraulic or electrically operated lifting jacks which are expensive and, in addition, requires a complicated control system for controlling the individual jacks to elevate the forms at an even rate around the structure.

In the present invention, the slip forms, work platform and associated equipment are supported independently of the poured silo wall and, by using concrete with a low slump characteristic, it has been possible to fabricate poured concrete silos at a rate in excess of One vertical foot per hour on a continuous basis or intermittent basis. Furthermore, the apparatus of the invention is relatively inexpensive and is easy to assemble and disassemble at the construction site and is easy to operate and control for elevating the slip form structure at the desired rate consonant with the pouring level of the concrete.

It is therefore an object of the present invention to provide a new and improved apparatus for constructing poured concrete silos and the like on a continuous or intermittent pouring basis.

Another object of the invention is to provision of a new and improved apparatus of the character described which makes it possible to construct poured concrete silos at a rapid rate of at least one vertical foot per hour on a continuous or intermittent basis until the desired structure height is obtained.

Yet another object of the present invention is the pro vision of a new and improved apparatus of the character 'ice described in which the slip forms, work platform and associated equipment are Supported independent of the poured concrete Walls of the silo.

Another object of the invention is the provision of a new and improved apparatus of the type described which is low 111 cost, easy to assemble and disassemble at the job site, easy to transport from job site to job site, and which is easy to operate and relatively trouble free in operation.

Yet another object of the invention is the provision of a new and improved apparatus of the type described which provides for the rapid construction of continuously or intermittently poured concrete silos and the like with a minimum of cost and labor required.

The foregoing and other objects and advantages ofthe present invention are accomplished by the provision of new and improved apparatus for constructing vertical, tubular, poured concrete structures, such as silos and the like, on a continuous or intermittent basis, including a slip form structure having vertically extending inside and outside spaced apart form walls. A horizontal work platform is mounted within the slip form structure and is connected around its periphery to the inside form wall for supporting the entire slip form structure independent of the wall being poured. An independent, ground supported, vertical scaffold s used for supporting the work platform, and the scaffold includes vertical sections adapted to be stacked upon one another as the pouring process proceeds upwardly, Each scaffold section includes a plurality of vertical posts for supporting the work platform and lifting means are provided interconnecting the work platform and scaffold posts for elevating the platform and slip form structure carried thlereon independently of the poured concrete wall of the s1 0.

In using the apparatus of the present invention, as the concrete is poured between the slip form walls at increasing elevations, the work platform and slip forms are moved upwardly on the supporting scaffold, and as the work platform approaches the upper ends of the posts in one scaffold section another additional scaffold section is stacked in place on top thereof and the vertical upward movement of the work platform and slip form then continues. Elevation of the platform and form structure is only momentarily interrupted as each additional scaffold section is added and reconnection between the lifting mechanism and additional section is made, During this brief period, the form structure may be maintained at its previous elevation by frictional contact between the poured wall of the silo and the inside and outside form walls of the slip form. As the pouring level proceeds upward, the poured silo walls uncovered below the slip form are banded with circumferential tension bands for additional strength, and heated air is introduced into the interior of the silo beneath the work platform to speed up the curing of the poured concrete.

For a better understanding of the present invention reference should be had to the following detailed description taken in connection with the accompanying drawing, in which:

FIG. 1 is a vertical sectional view illustrating the apparatus of the present invention as it is used for constructing a continuously poured concrete silo;

FIG. 2 is a sectional plan view of the apparatus of FIG. 1 taken substantially along line 2-2 of FIG. 3; and

FIG. 3 is a fragmentary elevational view taken substantially along line 33 of FIG. 1 and illustrating a portion of the work platform, scaffold post structure, and lifting mechanism in the apparatus of the invention.

Referring now more particularly to the drawings, therein is illustrated one embodiment of a new and improved apparatus for constructing poured concrete silos and the like in accordance with the features of the present invention, and indicated generally by the reference numeral 10. The apparatus includes a cylindrical slip form structure 12 comprising a vertically extending, cylindrical inner form wall 14 and an outer cylindrical form wall 16 spaced from the inner wall and in vertical concentric alignment therewith. In actual practice, the form walls 14 and 16 are made up of several wall forming panels or sections which are bolted together at the job site and may be disassembled from one another after the job is complete so that the apparatus may be easily moved and transported by truck or other vehicle to the next job site. The inside and outside form sections or panels making up the cylindrical form walls 14 and 16 are constructed of sheet steel which is rolled on the proper radius to provide the desired silo diameter, and suitable stiffening members and framework are provided to add the necessary strength to the panel sections. Silos having a diameter of 24 feet and wall thicknesses ranging from six to eight inches have been constructed with apparatus in accordance with the present invention, and the diameters of the form walls 14 and 16 obviously may be increased or decreased to provide for different diameters and wall thicknesses, as required.

The inside and outside form walls 14 and 16 are tied together around their top edges, as shown in FIG. 1 by a plurality of radially extending wall spacers 18 provided at spaced locations around the circumference of the form walls to complete the integral slip form structure 12 which is adapted to be elevated as an integral unit during pouring of the concrete between the form walls. Generally, before construction of the silo walls is started, an annular footing or base 20 of poured concrete is completed and a floor slab 22 may be poured in place before or after construction of the silo wall is completed.

Conveniently, the form panels or sections making up the cylindrical form walls 14 and 16 are assembled in place while resting on the footing 20, and after assembly are tied together by the spacers 18 to form the integral slip form structure 12. A circular, horizontal work platform 24 is assembled within and connected around its periphery to the inside form wall 14 for supporting the entire slip form structure 12 independently of the silo walls, and the platform 24 is, in turn, adapted to be supported on a scaffold structure 30 centrally disposed within the silo.

The work platform 24 comprises a plurality of radially extending chords, such as bar joists 26, which extend outwardly of a centrally located annular collar or ring 28, and the outer ends of the chords are bolted or otherwise connected to the inside form wall 14 to support the slip form structure 12 for elevation. The work platform also includes a removable floor formed of wood planks 32 or the like which are laid across the top of the chords to afford a convenient surface for the workmen to stand on.

The scaffold structure 30 comprises a plurality of vertical sections, each having a plurality of vertically extending posts 34 which are tied together by X-braces and horizontal cross braces 37 in a conventional manner, and as the work platform and form structure are elevated during construction of a silo, additional scaffold sections are stacked vertically on top of one another to obtain the desired height. The work platform 24 is provided with framed openings 36 (FIG. 2) in order to permit the scaffold posts 34 to extend upwardly through and above the platform, and each opening is flanked on opposite sides by suitable cross members 38 and 40 extending generally transversely between selected pair of adjacent chords 26.

Preferably, the scaffold posts 34 are of hollow tubular construction, such as round, steel pipes or columns, and a plurality of holes 34a extending transversely through the posts are provided at spaced intervals along the length of each post to permit the X-braces and cross braces 37 to be attached to tie the posts together. In order to facilitate vertical stacking of the posts in section one upon those of a next adjacent lower section, each post is provided with a plug member 42 adjacent its upper end, which extends upwardly beyond the end of the post and is adapted to seat in the lower ends of the posts of additional scaffold sections which are added to the scaffold structure as the construction proceeds.

After the slip form structure 12 and work platform 24 have been assembled and interconnected in place on the footing 22 at a job side, the posts 34 of the first or lowest scaffold section are set in place through the openings 36 in the work platform. The lower ends of the posts are supported on leveling jacks 44 which may be adjusted to insure that the scaffold structure 30 is plumb or vertical, and once the posts of the lowest scaffold section are in place they are tied together adjacent their lower ends beneath the work platform by lower horizontal cross braces 37a. Later on, as the platform 24 moves upwardly, additional X-braces and cross braces 37 are added below the platform to strengthen the scaffold structure.

The slip form structure 12 and its supporting work platform 24 are supported entirely independently of the wall of the silo being poured, by means of the scaffold structure 30, and in order to elevate the work platform on the scaffold a lifting mechanism is provided to interconnect the platform with each of the vertical posts 34 of the scaffold structure.

The lifting mechanism 50 comprises a puller mechanism including a single, centrally located, vertically extending, hydraulic cylinder 51 having an upper closed end supported from the apex of an A frame-type tower structure having a plurality of upwardly extending, sloping legs 52 connected together at their upper ends. The lower ends of the legs 52 are supported on and connected to the annular ring 28 of the work platform so that the A frame tower moves upwardly on the platform as it is elevated. The cylinder 51 includes a vertically movable piston rod 54 having a connector ring mounted on its lower end and a plurality of inner lifting cables 58 are connected to the ring and extend downwardly therefrom through a small center guide ring 60 in the work platform concentric with and spaced internally of the annular ring 28. The inner lifting cables 58 pass through the guide ring of the work platform and extend radially horizontally outward underneath the platform toward the individual posts 34 of the scaffold structure. For directing the cables radially outward along the underside of the platform, a plurality of sheaves 62 are mounted on the underside of selected chords 26 and the inner lifting cables pass downwardly around the sheaves and then outwardly toward respective posts of the scaffold.

Each inner lifting cable 58 is provided with a pulley block 64 at its outer end and each pulley block is connected with a respective outer lifting cable 66 which, in turn, is connected to the upper end of one of the individual posts 34 of the scaffold. Each outer lifting cable 66 is formed in a loop and the upper end of each leg of the loop is provided with an eyelet connector 68 adapted to be mounted on a headed, cross pin 70 which is inserted into a selected one of the holes 340 provided in the scaffold posts 34 (as best shown in FIG. 3). The legs of each outer lifting cable 66 pass downwardly along the adjacent scaffold post and through an adjacent opening 36 in the work platform, and then are directed radially inwardly along the underside of the platform for connection around the pulley or sheave of one of the pulley blocks 64. For directing each outer lifting cable radially inwardly, a pair of sheaves 72 are mounted on the underside of the work platform adjacent each of the openings 36, and each of the cables 66 is looped around the pulley in one of the pulley blocks 64 at the outer end of an inner lifting cable 58.

In order to supply the power needed to elevate the work platform 24 and slip form structure 12, the lifting mechanism 50 includes a motor-driven hydraulic pump 53 and fluid lines 55 and 57 interconnecting the pump with opposite ends of the cylinder 51. Suitable hydraulic controls and a fluid reservoir are provided so that pressurized fluid can be directed into either end of the cylinder at controlled rates. When fluid is directed into the lower end of the cylinder via the line 57, the piston rod 54 is retracted upwardly into the cylinder and, as this occurs, the upper end of the inner cables58 are pulled upwardly relative to the platform, through the center ring 60. Accordingly, the pulley blocks 64 are moved radially inwardly toward the center of the work platform and exert pull on the outer cables 66, causing the platform and slip form structure to be elevated slowly with respect to the scaffold structure 30.

In order to transport concrete from ground level to the pouring level at the top of the slip form structure, the apparatus includes an outwardly extending boom 80 supported at the top of the A frame structure, and the boom is mounted for free rotation around the work platform as the pouring proceeds. A power operated winch 82 is carried on the boom and includes a cable 84 which passes around a pulley 86 positioned adjacent the outer end of the boom. The lower end of the cable 84 is connected to a dump bucket 88 which is adapted to receive ready mixed, low slump concrete from a mixer or concrete truck 92. A pair of circular tracks or rails 94 are provided to extend around the upper end of the slip form structure 12 in order to accommodate a hopper assembly 96 which is movable along the rails to distribute the concrete around the slip form structure between the form walls 14 and 16.

In constructing a silo in accordance with the present invention, after the annular base or footing 20 has been poured in place at the job site, the inner and outer form walls 14 and 16 are assembled in place and tied together with the spacers 18 to complete the integral slip form structure 12. The work platform 24 is then assembled Within the slip form structure and connected to the inside form Wall 14. Posts 34 of the first scaffold section are then installed in place through the openings 36 in the platform with their lower ends resting on the jacks 44. The posts are tied together with the lower horizontal cross braces 37a. The lifting structure 50 is then interconnected with the upper end of the posts 34 by inserting the pins 70 in the openings 34a adjacent the top of the posts and thereby connecting the upper ends of the legs of the outer lifting cables 66 with the eyelets 68 journaled on the pins. The A frame structure is mounted on the platform and the boom is attached, and the inner and outer lifting cables are trained in place over the respective sheaves and connected With the lifting cylinder. The apparatus is now in readiness for the pouring of concrete which proceeds by delivering concrete from the truck 92 or mixer into the dump bucket 88 and hoisting the bucket by means of the cable 84 and winch 82 to deliver the contents thereof in the hopper 96, which is movable around the rails to distribute the concrete between the form walls 14 and 16. As the level of the concrete poured approaches the top of the form structure 12, the hydraulic pump 53 is started and hydraulic fluid is introduced into the lower end of the lifting cylinder 51, causing the work platform 24 and slip form structure 24 to move upwardly on the scaffold at a controlled rate as the pouring proceeds. When the work platform 24 closely approaches the upper ends of the posts 34 of the first scaffold section, an additional scaffold section is stacked on top of the lower scaffold section with the posts 34 of the next section held in place on the members 42. The pins 70 are disconnected from the posts of the lower scaffold section and the outer lifting cables are then reconnected to the posts of the additional section by inserting the pins into the poles 34a adjacent the top of the posts of the new scaffold section. Elevation of the slip form structure and platform is momentarily discontinued during this time, and the slip form structure and work platform is supported by frictional contact between the poured silo walls and the adjacent surfaces of the inner and outer form Walls 14 and 16. In order to prevent the form structure and work platform from slipping downwardly while the cables are being reconnected to the posts of the next scaffold section, stop pins may be inserted into openings 34a in the posts beneath the work platform to thereby limit the downward movement of the platform during the momentary period when the outer cables 66 are disconnected. In order to facilitate disconnection of the cables so that they may be reconnected to the next higher scaffold section, hydraulic fluid can be directed into the upper end of the lift cylinder 51 through the hydraulic line 55 in order to slack off tension on the cables 58 and 66. When this is done, the pins 70 are easily removed from the posts of the lower scaffold section and are then reinserted into openings 34m in the posts of additional scaffold sections. Cross braces and horizontal braces 37 are connected to the scaffold posts in each section to firmly and securely tie the posts 34 together, and this process can take place during elevation of the slip form structure. After the cables are reconnected to the posts of the next scaffold section, hydraulic fluid is directed through the line 57 into the lower end of the lifting cylinder, and the slip form structure and Work platform is moved upwardly as pouring proceeds. Pouring of concrete is continuous during the lifting or elevation of the slip form structure, and the concrete used has a low slump characteristic enabling the concrete to support its own weight.

Silos have been constructed in accordance with the present invention wherein the slip form structure 12 has been elevated upwardly at speeds of greater than one foot per hour. It has been contemplated that even higher speeds may be obtained. In order to strengthen the exposed outer wall portions of the silo beneath the upwardly moving slip form structure 12, steel tension bands are put in place and tightened around the poured wall as the pouring proceeds. In addition, in order to aid in rapidly curing the poured concrete, access openings 102 (FIG. 1) are provided around the base of the poured structure and heated air is introduced into the interior of the silo beneath the work platform, by one or more heater units 104. The introduction of heated air into the interior of the silo aids in rapidly curing the concrete and permits a rapid pouring rate and elevation of the slip form as described. Introduction of heated air into the interior of the silo beneath the WOl'k platform provides heat for the workmen on the platform and permits silos to be constructed in cold and inclement weather without too much discomfort on the part of the working men.

As the Work platform approaches the upper end of the posts 34 in each additional scaffold section, new scaffold sections are added; and each time the outer cables 66 are momentarily disconnected, and reconnected to the upper ends of the posts in the next scaffold. The pouring at ever increasing levels is continuous until the desired Wall height is obtained, and when this occurs the outer form wall 16 is disassembled and the panels are loaded onto the work platform. The platform is then lowered and the scaffold sections are disassembled one by one and loaded onto the platform until the platform reaches the ground where the entire assembly is disassembled. If outer tension bands 100 have not been utilized, it is not necessary to first remove the outer form wall 16 before lowering the platform, and the slip form structure can be lowered as a unit until reaching the ground.

From the foregoing, it will be seen that the invention provides a new and improved apparatus for constructing poured concrete silos on a continuous basis. The apparatus is simple and easily assembled and disassembled, making it possible to construct silos rapidly and then readily remove the equipment to another job site. Since the slip form structure 12 and work platform 24 are supported completely'independently of the poured silo wall, it is possible to proceed wtih pouring at an increased rate, and it is contemplated that slip forms can be raised at rates of two to three feet per hour during construction of a silo in accordance with the present invention.

While there has been illustrated and described a single embodiment of the present invention, it will be appreciated that numerous changes and modifications will occur to those skilled in the art, and it is intended in the appended claims to cover all those changes and modifications which fall within the true spirit and scope of the present invention.

What is claimed as new and desired to be secured by Letters Patent of the United States is:

1. Apparatus for constructing vertically extending poured concrete silos and the like comprising, a vertically extending slip form assembly including inside and outside form walls spaced apart and interconnected to move upwardly together as pouring proceeds, horizontal platform means connected around its periphery with said inside wall of said form assembly for supporting said assembly as said platform is elevated, ground supported scaffold means centrally disposed within said silo including a plurality of vertical sections adapted to be vertically stacked upon one another for supporting said platform means, each of said scaffold sections including a plurality of vertical posts adapted to be stacked on the posts of a lower section and projecting upwardly through openings in said platform means, lifting means interconnected between said platform means and each of said posts in a scaffold section for elevating said platform as pouring of concrete in said slip form assembly proceeds, said lifting means comprising a single pulling means mounted on said platform means and including means movable vertically with respect thereto, and a plurality of cable means connected with said last-mentioned means and extending outwardly therefrom for connection with the posts in a scaffold section.

2. The apparatus of claim 1 wherein each of said cable means passes around sheaves mounted on the underside of said platform means, at least one sheave positioned adjacent each post of a scaffold section and another sheave positioned adjacent said force means.

3. The apparatus of claim 1 wherein said pulling means comprises fluid cylinder means and piston rod means movable vertically in said cylinder means in response to fluid pressure therein to elevate said platform means on said scaffold means.

4. The apparatus of claim 3 wherein said pulling means includes fluid pump and control means mounted on said platform means for supplying pressurized fluid to opposite ends of said cylinder means to raise and lower said piston rod means therein.

5. The apparatus of claim 1 wherein each post of said scaffold means is formed with a plurality of vertically spaced, transverse openings therein, and removable pin connector means adjacent the outer end of each cable means adapted to be inserted in a selected one of said openings for connecting said cable means to said post.

6. The apparatus of claim 1 wherein each of said cable means includes a pair of cables interconnected by block means intermediate a post of said scaffold means and said pulling means.

7. The apparatus of claim 6 wherein the ends of one cable in each cable means are connected to a post of said scaffold means above said platform means.

References Cited UNITED STATES PATENTS 1,062,040 5/1913 Sellman 182-128 J. HOWARD FLINT, JR., Primary Examiner US. Cl. X.R. 

